Chain elongation of eicosapentaenoic acid in the macrophage.
In order to elucidate the metabolic fate of eicosapentaenoic acid (20:5 (n-3], a major n-3 fatty acid constituent of fish oil, resident and casein-elicited mouse peritoneal macrophages were incubated with [3H]20:5 (n-3). Comparative experiments with arachidonic acid (20:4 (n-6] were also conducted. After 4, 8 and 18 h incubation, [3H]20:5 (n-3) was extensively elongated into [3H]22:5(n-3) while [3H]20:4(n-6) was only moderately elongated into [3H]22:4(n-6) in both resident and elicited macrophages. No measurable conversion of [3H]22:5(n-3) into [3H]22:6(n-3) (delta 4 desaturation) could be demonstrated. These data demonstrate that the highly active chain elongation of 20:5(n-3) by macrophage elongase, as well as the lack of detectable delta 4 desaturase activity, are responsible for the accumulation of 22:5(n-3) in this cell.
Chapkin
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Department of Animal Science, Texas A&M University, Texas Agricultural Experiment Station, College Station 77843-2471.
Miller
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CC
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D015118:Eicosapentaenoic Acid / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005260:Female; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010529:Peritoneal Cavity / Q000166:cytology
D005231:Fatty Acids, Unsaturated; D015118:Eicosapentaenoic Acid